Installing 12V and USB power in the boot and a towbar.

[Thisisnotaspoon]

Just a quick post as I did a quick search and couldn't find the info so it might be useful for someone.

12V from the battery, a couple of 6mm ring crimp's (toolstation 59929), some spade connectors (with added heat shrink insulation as I didn't have the insulated type to hand) and some 10A blade fuses. I'll change it to a proper fuse holder at some point.

The cable is speaker cable, it's not quite as robust as automotive cable, but from experience on my last car you lose a lot of volts if you use the recommended gauge, and speaker cable is a significantly cheaper way of getting a lot of copper!

One cable feeds the bypass relay, the other feeds the 12V socket and USB.  

Both fused at 15A, the cable could comfortably take many times that but I was being cautious. 




Dropping down and out the back of the 'transmission tunnel' (I'm more used to working on RWD cars!) following what I presume is one of the brake lines (could be diesel).  I had to drill an extra hole and file it out to a rectangle to get the cable through the boot floor. Many layers of gorilla tape were added to stop it chafing through.



A bit of a rat's nest. Colour coding is:

Right hand side:
Indicator - cream
Reverse - White
Tail - Pink
Brake - Orange
Fog - Brown

Left hand side:
Indicator - yellow.

I ran the wire for the LH indicator out the light cluster foam seal, and pulled off the boot seal to tuck it behind, around the top and in the foam seal on the other side. I didn't bother splitting the two tail lights and just wired the brown and black relay wires (L and R tail) together.  I figured if there ever was a scenario where I wanted just one tail light on having both on the trailer wasn't going to be an issue!

Weirdly, input and output wiring on the relay doesn't follow the same colour code.

Double earth wire for the 12V socket just because I could, single for the USB.

Power gets from the 12V to the USB via a piggyback spade connector.

Had to tape the sockets in as I long ago lost the nuts!


Ta Daaaaaa!



Still to do:

Add propper inline fuse holders.

Add a leisure battery to the boot and a split charge relay so that whatever is plugged in doesn't drain the chasis battery.

[cancunia]

Nice job, I like the speaker cable idea!

[mission]

Nice project, but your wiring does worry me;

The wiring underneath the car really should be protected with plastic tubing or something. The plastic outerlayer rips easily and can get punched by little rocks and crap kicking up from the road.

And the wiring in the boot; that wirecauge is too thin for those terminal blocks. Id use some crimp connectors (or even better those solder crimp connectors). Makes it easier to clean that spaghetti as well.

[Romahomepete]

Nice project, but your wiring does worry me;

The wiring underneath the car really should be protected with plastic tubing or something. The plastic outerlayer rips easily and can get punched by little rocks and crap kicking up from the road.

And the wiring in the boot; that wirecauge is too thin for those terminal blocks. Id use some crimp connectors (or even better those solder crimp connectors). Makes it easier to clean that spaghetti as well.

It is possible to come through the firewall with a proper fitting and follow the route of the wiring loom.  That is what I did
Peter

[mission]

Nice project, but your wiring does worry me;

The wiring underneath the car really should be protected with plastic tubing or something. The plastic outerlayer rips easily and can get punched by little rocks and crap kicking up from the road.

And the wiring in the boot; that wirecauge is too thin for those terminal blocks. Id use some crimp connectors (or even better those solder crimp connectors). Makes it easier to clean that spaghetti as well.

It is possible to come through the firewall with a proper fitting and follow the route of the wiring loom.  That is what I did
Peter

Yup, you can either drill a hole, or use one of the existing ones

[Gadgetman]

When I installed 12V and 230V(150W inverter hidden behind a panel) I installed it on the driver's side(lefthand side on my M49), and pulled the cable forward inside the wall, behind the wall panel beside the rear seat and down to the door sill. Remove the sill and it's possible to fit cables there. Then up under the dash and follow along with the wiring loom into the engine compartment.

the Speaker wire, did you get OFC or CCA cable?
Oxygen-Free Copper / Copper Clad Aluminium.
you need thicker wires if it's CCA because Aluminium isn't as good a conductor as Copper.
And the insulation is NOT what you'd call 'designed for the environment' you've put it in.

[Pedronicus]

The wiring underneath the car really should be protected with plastic tubing or something. The plastic outerlayer rips easily and can get punched by little rocks and crap kicking up from the road.

Could not agree more added to the fact that the cable ties will eventually harden and fall apart (unless they are ones specifically meant for external use) thereby dropping the cables onto the road.

[Romahomepete]

When i fitted mine and I drilled the firewall I fitted a proper cable gland not a grommet.

Peter

[mission]

The wiring underneath the car really should be protected with plastic tubing or something. The plastic outerlayer rips easily and can get punched by little rocks and crap kicking up from the road.

Could not agree more added to the fact that the cable ties will eventually harden and fall apart (unless they are ones specifically meant for external use) thereby dropping the cables onto the road.

Looking at the photo's he might even be able to use the existing tubing